Why do some website addresses have “www” and some don’t? And why do some work with or without the “www”?

The "www" in website addresses is now typically optional, but there was once a reason as to why they were required in URLs.

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Why do some website addresses have “www”, and some don’t? And why do some work with or without the “www”?

Most of the time, it’s an oversight. Occasionally, it’s on purpose, but to be honest, I haven’t run across an “on purpose” in years.

It’s common practice now that “www” is optional; mostly because it’s redundant and URLs are long enough without adding redundant information.

But once upon a time, there was a reason.

The original intent was that the “www” specified what you were trying to do, so you could be sent to the right computer to do that. Servers that were available for “World Wide Web” access used a “www” prefix. Servers that were available for “File Transfer Protocol” access used a “ftp” prefix. Even on the same base domain, www.example.com and ftp.example.com might well be completely different machines. The prefix was both a mnemonic device to help us remember what we’re doing as well as a way to route us to the right server.

The question, of course, is what to do when no prefix is specified. The way internet names work, www.askleo.com and askleo.com are technically two different names and two different sites. As the owner of the base domain name askleo.com, I needed to take a couple of extra steps to make them both behave the same way when you visit either with your browser.

Over time, the web and all those “www” servers became the predominant traffic on the internet, so more and more sites began to respond to references both with and without the “www.” As I said, it’s become common practice, almost a pseudo-standard.

About Leo

Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

That’s an IP address. All computers on the internet are REALLY identified by IP addresses. The text names you and I use, like “www.ask-leo.com” get converted to IP addresses in order to really locate the computer. Most of the time you don’t need to know or care about this.

man i am facing this same problem. i can’t visit my website without using wwww infront of the url. i asked for help from my hosting service, but the guy said it is working fine. so it looks like it is just my computer. hah

To Sarit: I’m assuming you have a windows machine. If so, go to Start, Run. Type cmd then hit Enter. This will bring up a command prompt window. Now type tracert http://www.rediffmail.com then hit Enter. This command tracert means “trace the route to the following domain or IP address”. After you hit enter, you will see a message saying “Tracing route to http://www.rediffmail.com [202.137.235.12]”. There is the IP address. The rest of the stuff tracert does is map every IP address between you and http://www.rediffmail.com (if the request doesn’t time out). There is probably another way to do it, but that’s the way I use.

The original intent was that the “www” specified what you were trying to do, so you could be sent to the right computer to do that. Servers that were available for “World Wide Web” access used a “www” prefix. Servers that were available for “File Transfer Protocol” access used a “ftp” prefix. Even on the same base domain, http://www.example.com and http://ftp.example.com might well be completely different machines. The prefix was both a mnemonic device to help us remember what we’re doing as well as a way to route us to the right server.

One thing you gloss over is the reason that the “www.” has become so redundant — namely, that its function has been almost entirely replaced by the protocol declarator. the “http://” at the start of the URL now does what the “www.” once used to do; and of course, when “ftp://” begins a URL, the URL itself surely doesn’t need to insist on the pattern of “ftp.whatever.com”!!! The “[protocol]://” prefix has pretty much obviated the need for that sort of idiocy. Yet it’s still rampant!

Hi there, thanks for the article,
Im still struggling to understand how the domains with and without www are different. I have some websites and some load as www and some load without it. My webmaster tools apparently understands the two sites seperately. If I change my domain from example.com to http://www.example.com in the domain manager will the original links be lost?
Thanks alot for your help
Will

As Leo says, *sometimes* the www. is redundant, sometimes it isn’t. It is the responsibility of the webmaster to straighten that out as Leo has, others have not. Probably it doesn’t make a whole lot of difference – except in one very important case: *secure* sites. A secure certificate for, say http://www.example.com will not work for example.com; they are different sites and the certificate ‘knows’ for which one it’s been issued for. More reasons to keep the webmaster happy.
As to IP addresses to Hostnames, I like to use http://whatismyipaddress.com for those things. (no www ) Yes, that site tells *your* IP, but you can use the IP-Tools tab to look up any IP address (to see if it’s a host) or any Host name to see what IP address has been assigned to that host. That, plus a pretty good email tracer, make whatismyipaddress a keeper.

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